hum or howl in 4wd

[Charlie207]

Drained the fluid today - front diff is cooked. Tons of sparkles, oil is completely silver. Time to go shopping. Going to get another used assembly and hope for the best.

That stinks, but eBay is your friend.

 

[DaveO9]

I might be getting a break - I called LKQ Online today and put in a warranty claim. Still some hoops to jump through, i.e. got to take it to a shop for an official diagnosis, but maybe it will work out. Called in the nick of time - it's a 6 mo warranty and tomorrow is exactly 6 months from the date on the invoice email. Although there might be a short grace period, the guy was asking me when I installed it.

I'll call a trans shop I've used before tomorrow, but has anyone ever had this experience of having to get a shop's diagnosis for a warranty claim? I'm hoping they can drive it, hear the noise and say, yep it's toast, and I'm done. It's not like you can just pop a cover off of these front units and look at the diff and bearings.

 

[Geotrash]

I might be getting a break - I called LKQ Online today and put in a warranty claim. Still some hoops to jump through, i.e. got to take it to a shop for an official diagnosis, but maybe it will work out. Called in the nick of time - it's a 6 mo warranty and tomorrow is exactly 6 months from the date on the invoice email. Although there might be a short grace period, the guy was asking me when I installed it.

I'll call a trans shop I've used before tomorrow, but has anyone ever had this experience of having to get a shop's diagnosis for a warranty claim? I'm hoping they can drive it, hear the noise and say, yep it's toast, and I'm done. It's not like you can just pop a cover off of these front units and look at the diff and bearings.

Yes, it's a common practice to require a shop diagnosis for warranty claims. Will they pay for that diagnosis too?

Fingers crossed!

 

[DaveO9]

Yes, it's a common practice to require a shop diagnosis for warranty claims. Will they pay for that diagnosis too?

Fingers crossed!

I haven't asked yet. I'll ask or maybe just submit the receipt, but even if they don't, it'll be better than paying the $400 for a different unit.

 

[DaveO9]

I was looking more closely at the oil I drained out the other night. There is tons of metal in there, but it is super fine, zero flakes or chunks. Reminds me of metallic silver paint that hasn't been thoroughly mixed. And a magnet doesn't pick any of it up. I'm guessing something is grinding a groove in the aluminum housing. I had a Dodge Dakota years ago that did that in the rear end. It ground a perfect groove in part of the housing, looked like it had been factory machined.

 

[DaveO9]

Sounds like warranty claim is turning out to be a no-go. LKQ customer rep said I ordered it custom, no VIN provided, so no warranty. I had to do that because I was changing axle ratios and they wouldn't sell it to me otherwise. I do remember that conversation when I was ordering it, but at that time, the rep sent me an email with a bunch of warranty stipulations for their 6 month parts-only warranty. And then, when I called a couple weeks ago to make the claim, I gave the (different) rep my original invoice number and he didn't say anything about no warranty. So I thought it was going to work out, but guess not. I'm going to try and call one more time tomorrow, but not optimistic.

So on the hunt for another used unit. Even though I'm a little pissed at LKQ now, I might just go with them again since they have such a large network and the lowest prices by far. (at least for these front units).

This next question has been asked before, including in one of my threads, but I don't think I've ever seen a definitive answer. 2013 front diffs had two different ID codes: AABR and BAAB. I've done a bit of sleuthing tonight, and it seems like they switched the design in '13. I have AABR which I think is the new one - it works in some '13 and all '14. BAAB is the old design and it works in some '13 and, I think, all the way back to '09, or possibly to '07. HOWEVER, I have not been successful in determining the difference between the two designs, and, more importantly, whether they are interchangeable. Anyone know?

 

[swathdiver]

Sorry Dave. I'd go with them again too. Lots to choose from and reasonably priced.

I "think" the difference is that older one has a single seal flange and the other a double seal flange. In the grand scheme of things, who cares? Get whichever is most convenient with the lowest miles and in the best condition.

I was fortunate to get one from Suburban a year older but with less miles than mine.

 

[DaveO9]

Sorry Dave. I'd go with them again too. Lots to choose from and reasonably priced.

I "think" the difference is that older one has a single seal flange and the other a double seal flange. In the grand scheme of things, who cares? Get whichever is most convenient with the lowest miles and in the best condition.

I was fortunate to get one from Suburban a year older but with less miles than mine.

Thanks, James! Good to know. So sounds like it’s almost surely a direct bolt-in either way?

 

[swathdiver]

Thanks, James! Good to know. So sounds like it’s almost surely a direct bolt-in either way?

Yeah, it only matters when getting parts to repair/rebuild them.

 

[TrybalRage]

I used my 4wd for the first time in a while during a snowstorm a few weeks ago, and these symptoms don't give me the warm and fuzzies after reading this.

In 4wd hi or auto - slight growling low vibration under acceleration, stops when foot is off the gas.
Goes away completely in 2wd.

Crap.

 

[DaveO9]

I used my 4wd for the first time in a while during a snowstorm a few weeks ago, and these symptoms don't give me the warm and fuzzies after reading this.

In 4wd hi or auto - slight growling low vibration under acceleration, stops when foot is off the gas.
Goes away completely in 2wd.

Crap.

Yeah, sounds pretty familiar. I just took my carrier out tonight and tomorrow will put in the replacement unit from LKQ. I split the two halves and looked inside, but haven't seen anything crazy obvious yet. I'll do some more checking tomorrow and report back.

Guys - I'm thinking since I have the diff out a second time, I'll go ahead and do the oil pickup tube o-ring. My oil pressure seems to be getting worse. It's just over 20 psi at highway cruise RPM now. Seems pretty low. I bought a Fel-pro oil pan gasket and o-ring today, so I think I'm ready. How hard is it to drop the oil pan? I know you have to get the timing cover off to get to the actual pump, but it looks like you DON'T have to do that if you're just replacing the o-ring? I know you do have to lower the steering rack to get the pan off, but that doesn't seem too crazy....

If anyone has any thoughts or advice for this one, please let me know.

 

[TrybalRage]

You should not have to remove the timing cover, no.

I put a junkyard 5.3 in my C10, and I replaced the pickup o-ring on that before I put it in the truck - I never took off the timing cover. That was a gen3 motor but I don't think it should be different.

I have no idea how hard it would be to get the pan off with the motor still in.

 

[DaveO9]

Everything put back together and voila!, no more noise from front diff. Can't hear the difference between 2wd and 4wd (auto or high) at all. And as discussed previously in this thread, this time I went the extra step of dropping the oil pan to replace the pickup o-ring. Now my oil pressure is a good 5-10 psi higher for a given rpm/temperature. The trifecta would be if replacing the pan gasket (Fel-Pro) resolved the small oil leak that has annoyed me since I've owned it. I'm optimistic since I'm pretty sure it was in the corner where the oil filter is, and it sounds like leaks there are common.

Sorry Dave. I'd go with them again too. Lots to choose from and reasonably priced.

I "think" the difference is that older one has a single seal flange and the other a double seal flange. In the grand scheme of things, who cares? Get whichever is most convenient with the lowest miles and in the best condition.

I was fortunate to get one from Suburban a year older but with less miles than mine.

James, in looking at them side by side (sorry forgot to grab a pic) I think you're correct. The hub where the stub shafts slide in was a good bit bigger on the newer version, so a double seal is probably a good bet. I'm pretty sure the passenger side extension is swappable between the two, so I COULD use the newer if I ever need to, but I seriously doubt it.

I took apart the removed carrier, expecting to find obvious damage, but I don't see anything ground up. The only thing that seems no bueno to me are the bearings the diff rides on are loose, but they're fully intact. If I needed to get this one going again, I'd replace those bearings and probably the ones for the stub shafts and put it back together. No damage to the R&P, and the pinion bearing seems solid, smooth, and tight. There are some weird marks on the open faces of the diff, but in closer inspection (and thinking about it) it seems that are just indicative of some not great factory machining.

 

[donjetman]

bearing looks like it got hot. IMO change it and any others that look like it.